i've never heard the corsair set so i cannot comment on it. personally i would trust logitech more when it comes to speakers and perepherals and corsair more when it comes to computer cases, power supplies and ram.
as far as audiophile quality goes...its not a simple yes or no question. we all have different tastes and different expectations but i can give you a few ideas.
i have a pair of audiotechnica ath-m50 headphones which for the $150 price are comparable to headsets into the $300 range. personally i would consider them audiophile quality.
i used to have an old logitech 5.1 set which i considered to be great for music and games as i never really noticed any things like distortion but i did get a crackle every once in a long time. for $99-120 or so i thought it was a great deal until i moved on to bigger and better things. i'd never go back now, but it was good while it lasted.
an upgrade to normal pc speakers would have to be the top of the line logitech sets. i've heard that the top tier models can compare with some home theater systems in terms of sound quality.
currently i'm running a home theater setup (receiver + 5 speakers + sub) for my pc and ps3 doing games, movies, etcetera. a pioneer vsx-30 receiver, klipsh quintet IV set and a 450w klipsh subwoofer. retail value around $1300 total. these arent the small cheap speakers in a HTIB set but decent quality ones (if on the lower scale of things). i'm very happy with the purchase.
that said, going out and buying a $100 receiver and hooking up some speakers like the ones we have in our living room would work fine. they are black sony tower speakers about 3.5 ft tall which came two in a box from sears.com. for $120 or so a PAIR definitely a great deal.
as you can see.....there are tons of options available depending on what your budget is and what you expect. i can recommend a few minimums on price but its entirely my own opinion and not fact. good for an idea but thats it.
headphones: $100-200
best 2.1 pc speakers: $200
best 5.1 pc speakers: $400
entry level ht 2.0 no sub: $250
with sub 2.1: $330
entry level ht 5.1 $500
keep in mind that these are just very loose estimates as i'm just basing my opinion on products i've seen/would buy myself. one thing i would avoid at all costs are normal HTIB sets. they do work sure...but they aren't exactly built well and arent of the same quality as speakers you buy individually.
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as for the 2.1 set you are thinking about buying.... it should definitely keep you satisfied until you find its time to move on to bigger and better things